scholarly journals DNA Metabarcoding Reveals Cryptic Geographically-influenced Microbial Diversity After Anthropogenic Impact in Original Forest Soils on the Isolated Trindade Island, South Atlantic

2022 ◽  
Author(s):  
Paulo Saraiva Camara ◽  
Fabio Bones ◽  
Fabyano Lopes ◽  
Fabio Oliveira ◽  
Cristine Barreto ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Forest Soils ◽  
High Throughput Sequencing ◽  
Sequence Data ◽  
Anthropogenic Impacts ◽  
South Atlantic ◽  
South American ◽  
The South ◽  
Trindade Island ◽  
Feral Animals

Abstract Located 1,140 km from the South American coastline in the South Atlantic Ocean, and with an age of 4 million years, Trindade Island is the most recent volcanic component of Brazilian territory. Its vegetation was severely damaged by human influence in particular through the introduction of exotic grazing animals such as goats. However, since the complete eradication of goats and other feral animals in the late 1990s, the island’s vegetation has been recovering and even some endemic species that had been considered extinct have been rediscovered. In this study we set out to characterize the contemporary microbial diversity of Trindade Island forest soils using metabarcoding by High Throughput Sequencing (HTS). Sequences of representative of two domains (Bacteria and Archaea) and five kingdoms (Fungi, Metazoa, Protozoa, Chromista and Viridiplantae) were identified. Bacteria were represented by 20 phyla and 116 taxa, while and Archaea by only one taxon. Fungi were represented by seven phyla and 250 taxa, Viridiplantae by five phyla and six taxa, Protozoa by five phyla and six taxa, Metazoa by three phyla and four taxa and Chromista by two phyla and two taxa. Even after the considerable anthropogenic impacts and devastation of the island’s natural forest, our sequence data revealed the presence of a rich, diverse and complex diversity of microorganisms, invertebrates and plants.

scholarly journals Aedes aegypti Invades Trindade Island, 1,140 km from the Brazilian Coast, in the South Atlantic

2020 ◽  
Vol 36 (2) ◽  
pp. 112-114
Author(s):  
Alexandre A. Oliveira ◽  
Hélcio R. Gil-Santana ◽  
Ruy J. Válka Alves ◽  
Jeronimo Alencar
Keyword(s):  
Aedes Aegypti ◽  
Health Risks ◽  
Adult Stage ◽  
South Atlantic ◽  
Brazilian Coast ◽  
The South ◽  
Potential Health ◽  
Active Search ◽  
Trindade Island ◽  
Eggs And Larvae

ABSTRACT Herein we report the first recorded arrival of Aedes aegypti on Trindade Island, approximately 1,140 km from the Brazilian coast, posing potential health risks to the human inhabitants thereof. The collection of mosquitoes was done from August to October 2019 via an active search for adults, eggs, and larvae by surveying objects with accumulated water and implantation of 23 ovitraps in different regions of the island. As a result, we collected 33 adults of Ae. aegypti via active search inside buildings. A total of 433 eggs of Ae. aegypti were also obtained from the ovitraps, all of which subsequently reached the adult stage. No other species of Culicidae was found.

Modelling thermal lithospheric thickness along the conjugate South Atlantic passive margins implies asymmetric rift initiation

2021 ◽  
Author(s):  
Peter Haas ◽  
R. Dietmar Müller ◽  
Jörg Ebbing ◽  
Gregory A. Houseman ◽  
Nils-Peter Finger ◽  
...  
Keyword(s):  
South Atlantic ◽  
Heterogeneous Structure ◽  
South American ◽  
The South ◽  
Passive Margins ◽  
Margin Width ◽  
Lithospheric Thickness ◽  
Lithospheric Thinning ◽  
Tectonic Features ◽  
And Diffusion

<p>In this contribution, we examine the evolution of the South Atlantic passive margins, based on a new thermal lithosphere-asthenosphere-boundary (LAB) model. Our model is calculated by 1D advection and diffusion with rifting time, crustal thickness and stretching factors as input parameters. The initial lithospheric thickness is defined by isostatic equilibrium with laterally variable crustal and mantle density. We simulate the different rifting stages that caused the opening of the South Atlantic Ocean and pick the LAB as the T=1330° C isotherm. The modelled LAB shows a heterogeneous structure with deeper values at equatorial latitudes, as well as a more variable lithosphere along the southern part. This division reflects different stages of the South Atlantic opening: Initial opening of the southern South Atlantic caused substantial lithospheric thinning, followed by the rather oblique-oriented opening of the equatorial South Atlantic accompanied by severe thinning. Compared to global models, our LAB reflects a higher variability associated with tectonic features on a smaller scale. As an example, we identify anomalously high lithospheric thickness in the South American Santos Basin that is only poorly observed in global LAB models. Comparing the LAB of the conjugate South American and African passive margins in a Gondwana framework reveals a variable lithospheric architecture for the southern parts. Strong differences up to 80 km for selected margin segments correlate with strong gradients in margin width for conjugate pairs. This mutual asymmetry suggests highly asymmetric melting and lithospheric thinning prior to rifting.</p>

scholarly journals The impact of the subtropical South Atlantic SST on South American precipitation

2008 ◽  
Vol 26 (11) ◽  
pp. 3457-3476 ◽  
Author(s):  
A. S. Taschetto ◽  
I. Wainer
Keyword(s):  
South America ◽  
Southern Oscillation ◽  
South Atlantic ◽  
Empirical Orthogonal Functions ◽  
Convergence Zone ◽  
South American ◽  
The South ◽  
Inter Tropical Convergence Zone ◽  
The Impact ◽  
Sst Anomalies

Abstract. The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and remote influences, however, are confounded by the large internal variance in the region. During MAM and JJA, the South Atlantic SST anomalies affect the magnitude and the meridional displacement of the ITCZ. In JJA, the ENSO has relatively little influence on the interannual variability of the simulated rainfall. During SON, however, the ENSO seems to counteract the effect of the subtropical South Atlantic SST variations on convection over South America.

scholarly journals South Atlantic Surface Boundary Current System during the Last Millennium in the CESM-LME: The Medieval Climate Anomaly and Little Ice Age

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 299
Author(s):  
Fernanda Marcello ◽  
Ilana Wainer ◽  
Peter R. Gent ◽  
Bette L. Otto-Bliesner ◽  
Esther C. Brady
Keyword(s):  
Little Ice Age ◽  
South Atlantic ◽  
Subtropical Gyre ◽  
Ice Age ◽  
Surface Boundary ◽  
South American ◽  
Last Millennium ◽  
Medieval Climate Anomaly ◽  
The South ◽  
Gyre Circulation

Interocean waters that are carried northward through South Atlantic surface boundary currents get meridionally split between two large-scale systems when meeting the South American coast at the western subtropical portion of the basin. This distribution of the zonal flow along the coast is investigated during the Last Millennium, when natural forcing was key to establish climate variability. Of particular interest are the changes between the contrasting periods of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The investigation is conducted with the simulation results from the Community Earth System Model Last Millennium Ensemble (CESM-LME). It is found that the subtropical South Atlantic circulation pattern differs substantially between these natural climatic extremes, especially at the northern boundary of the subtropical gyre, where the westward-flowing southern branch of the South Equatorial Current (sSEC) bifurcates off the South American coast, originating the equatorward-flowing North Brazil Undercurrent (NBUC) and the poleward Brazil Current (BC). It is shown that during the MCA, a weaker anti-cyclonic subtropical gyre circulation took place (inferred from decreased southern sSEC and BC transports), while the equatorward transport of the Meridional Overturning Circulation return flow was increased (intensified northern sSEC and NBUC). The opposite scenario occurs during the LIA: a more vigorous subtropical gyre circulation with decreased northward transport.

scholarly journals Projected End-of-Century Changes in the South American Monsoon in the CESM Large Ensemble

2020 ◽  
Vol 33 (18) ◽  
pp. 7859-7874
Author(s):  
Ana Claudia Thome Sena ◽  
Gudrun Magnusdottir
Keyword(s):  
South America ◽  
South Atlantic ◽  
Northeastern Brazil ◽  
Southeastern Brazil ◽  
South American ◽  
The South ◽  
Wet Season ◽  
Large Ensemble ◽  
South American Monsoon ◽  
The Mean

AbstractProjected changes in the South American monsoon system by the end of the twenty-first century are analyzed using the Community Earth System Model Large Ensemble (CESM-LENS). The wet season is shorter in LENS when compared to observations, with the mean onset occurring 19 days later and the mean retreat date 21 days earlier in the season. Despite a precipitation bias, the seasonality of rainfall over South America is reproduced in LENS, as well as the main circulation features associated with the development of the South American monsoon. Both the onset and retreat of the wet season over South America are delayed in the future compared to current climate by 3 and 7 days, respectively, with a slightly longer wet season. Central and southeastern Brazil are projected to get wetter as a result of moisture convergence from the strengthening of the South Atlantic low-level jet and a weaker South Atlantic subtropical high. The Amazon is projected to get drier by the end of the century, negatively affecting rain forest productivity. During the wet season, an increase in the frequency and intensity of extreme precipitation events is found over most of South America, and especially over northeastern and southern Brazil and La Plata. Meanwhile, during the dry season an increase in the maximum number of consecutive dry days is found over northeastern Brazil and the northern Amazon.

scholarly journals New constraints on elemental and Pb and Nd isotope compositions of South American and Southern African aerosol sources to the South Atlantic Ocean

Geochemistry ◽  
2018 ◽  
Vol 78 (3) ◽  
pp. 372-384 ◽  
Author(s):  
R. Khondoker ◽  
D. Weiss ◽  
T. van de Flierdt ◽  
M. Rehkämper ◽  
K. Kreissig ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
South American ◽  
The South ◽  
Nd Isotope ◽  
Aerosol Sources
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